Balloon catheter inflation apparatus and methods

ABSTRACT

An inflation device includes a syringe body containing a bore. The bore holds a fluid that is used to inflate a separate device such as a dilation balloon. A plunger assembly slides within the syringe bore and contains a sealing member that forms a fluid tight seal with the syringe body. A shut-off valve is disposed within the distal end of the syringe body. The distal end of the syringe body has a fluid bypass channel fluidically coupled to the aperture of a connector. The shut-off valve has a spring-biased moveable piston with a bypass lumen contained therein, wherein the bypass lumen forms a fluid path between the bore and the fluid bypass channel when the pressure of the fluid is below a threshold value. The fluid path between the bore and the fluid bypass channel is interrupted when the pressure of the fluid is above the threshold value.

RELATED APPLICATIONS

This Application is a continuation of U.S. patent application Ser. No.15/642,616 filed on Jul. 6, 2017, which is a continuation of U.S. patentapplication Ser. No. 14/796,948 filed on Jul. 10, 2015, which is acontinuation of a U.S. patent application Ser. No. 12/372,691 filed onFeb. 17, 2009, the contents of which are hereby incorporated byreference in their entirety.

FIELD OF THE INVENTION

The field of the invention generally relates to balloon inflationdevices and methods. Balloon inflation devices are typically used inconstricted spaces within the human or mammalian body. Balloon dilationhas become popular in numerous medical fields of application. Oneparticular use of balloon dilation is the treatment of sinusitis.

BACKGROUND OF THE INVENTION

Sinusitis is a condition affecting over 35 million Americans, andsimilarly large populations in the rest of the developed world.Sinusitis occurs when one or more of the four paired sinus cavities(i.e., maxillary, ethmoid, frontal, sphenoid) becomes obstructed.Normally the sinus cavities, each of which are lined by mucosa, producemucous which is then moved by beating cilia from the sinus cavity out tothe nasal cavity and down the throat. The combined sinuses produceapproximately one liter of mucous daily, so the effective transport ofthis mucous is important to sinus health.

Each sinus cavity has an opening into the nasal passage called anostium. When the mucosa of one or more of the ostia or regions near theostia become inflamed, the egress of mucous is interrupted, setting thestage for an infection and/or inflammation of the sinus cavity, i.e.,sinusitis. Infection/inflammations of the maxillary with or without theethmoid sinuses make up the vast majority of cases of sinusitis, withfar fewer cases involving the sphenoids and frontals. Though manyinstances of sinusitis may be treatable with appropriate medicates, insome cases sinusitis persists for months or more, a condition calledchronic sinusitis, and may not respond to medical therapy. Some patientsare also prone to multiple episodes of sinusitis in a given period oftime, a condition called recurrent sinusitis.

Balloon dilation has been applied to treat constricted sinus passagewaysfor the treatment of sinusitis. These balloon dilation devices typicallyinvolve the use of an inflatable balloon located at the distal end of acatheter (a balloon catheter). Generally, the inflatable balloon isinserted into the constricted sinus passageway in a deflated state. Theballoon is then expanded to open or reduce the degree of constriction inthe sinus passageway being treated. A variety of devices (inflationdevices) have been used to inflate and deflate the inflatable balloonlocated on the catheters. Many of these devices used in these treatmentshave been bulky and cumbersome to use. Often an assistant to thephysician is utilized to perform the inflating/deflating of the ballooncatheter, as the overall systems include multiple componentsnecessitating multiple operators working in conjunction with oneanother.

Existing inflation devices typically include a rather large volumesyringe having a barrel that is filled with an incompressible fluid suchas saline. The syringe includes a plunger assembly having a shaftportion that terminates at one end with a sealing member located withinthe syringe barrel. The sealing member is sealed (or acts as a seal)within the interior of the bore. The other end of the stem is typicallysecured to a depressor or the like that enables the user to actuate thesyringe. The inflation devices also typically include a pressure gauge.The pressure gauge measures, indirectly, the pressure within theinflatable balloon. Pressure to the inflatable balloon is adjusted bythe degree of insertion of the plunger assembly within the barrel of thesyringe. The pressure is indicated by the pressure gauge, and the usercan adjust the pressure accordingly by relative movement of the plungerwith the syringe barrel. A syringe having a large volume (and thus islarge and bulky) is typically chosen to provide for adequate vacuumpressures that overcome the volume compliance of the pressure gauge, andto a lesser extent the volume compliance of the remainder of the closedsystem including the balloon dilation catheter itself. As a result,existing inflation devices are bulky and cumbersome to work with,requiring a dedicated operator just for its operation. Thus, medicalinterventional procedures that require use of balloon dilation mayrequire additional personnel to operate the balloon inflation device inaddition to other interventional devices.

There thus is a need for an inflation device that would simplify thedilation of an expandable member such as a dilation balloon. Such adevice should be more compact than existing inflation devices and enablea single user to operate the inflation device duringinflation/deflation. Such a device and any system that would incorporatethe device would be particularly useful and advantageous in procedureswhere the dilation balloon is used to dilate constricted spaces,particularly constricted spaces in the sinus cavities.

SUMMARY OF THE INVENTION

In a first embodiment of the invention, an inflation device includes asyringe body having proximal end and a distal end and a bore containedtherein, the bore configured to hold a fluid therein. The inflationdevice includes a plunger assembly comprising a shaft having a proximalend and a distal end, the proximal end of the shaft operatively coupledto an actuator, the distal end of the plunger assembly comprising asealing member configured to form a fluid tight seal with the syringebody. A connector is disposed at the distal end of the inflation device,the connector containing an aperture configured for passage of fluid.The inflation device includes a shut-off valve disposed within a valvebody, the shut-off valve in fluid communication with the syringe body,the valve body including an aperture therein that communicates with anoutlet channel external to valve body that is fluidically connected tothe aperture of the connector. The shut-off valve has a spring-biasedmoveable piston having a bypass lumen contained therein, wherein thebypass lumen forms a fluid path between the bore and the outlet channelwhen the pressure of the fluid is below a threshold value and whereinthe fluid path between the bore and the outlet channel is interruptedwhen the pressure of the fluid is above the threshold value.

In a second embodiment of the invention, a system for dilating a naturalsinus ostium includes a balloon dilation catheter having an elongatemember having a dilation balloon at one end and a first connector at anopposing end. The system further includes an inflation device with asyringe body having proximal end and a distal end and a bore containedtherein, the bore configured to hold a fluid therein. The inflationdevice includes a plunger assembly configured for slidable movementwithin the syringe bore, the plunger assembly comprising a shaft havinga sealing member configured to form a fluid tight seal with the syringebody. A second connector is disposed at the distal end of the inflationdevice, the second connector containing an aperture configured forpassage of fluid, the second connector configured to mate with the firstconnector of the balloon dilation catheter. A fluid bypass channel isdisposed in the distal end of the syringe body and fluidically coupledto the aperture of the second connector. The inflation device includes ashut-off valve made from a spring-biased moveable piston having a bypasslumen contained therein, wherein the bypass lumen forms a fluid pathbetween the bore and the fluid bypass channel in the syringe body whenthe pressure of the fluid is below a threshold value and wherein thefluid path between the bore and the fluid bypass channel is interruptedwhen the pressure of the fluid is above the threshold value.

In another embodiment of the invention, a system for dilating arestricted part of the human anatomy includes a balloon dilationcatheter and an inflation device. The inflation device is configured forfluidic attachment to the balloon dilation catheter, the inflationdevice has a syringe body having proximal end and a distal end and abore contained therein, the bore configured to hold a fluid therein. Theinflation device also has a plunger assembly comprising a shaft having aproximal end and a distal end, wherein the proximal end of the shaft isoperatively coupled to an actuator and the distal end of the plungerassembly has a sealing member configured to form a fluid tight seal withthe syringe body. A connector is disposed at the distal end of theinflation device, the connector containing an aperture configured forpassage of fluid. The inflation device includes a shut-off valvedisposed within a valve body, the shut-off valve in fluid communicationwith the syringe body. The valve body includes an aperture therein thatcommunicates with an outlet channel external to valve body that isfluidically connected to the aperture of the connector, the shut-offvalve having a spring-biased moveable piston having a bypass lumencontained therein, wherein the bypass lumen forms a fluid path betweenthe bore and the outlet channel when the pressure of the fluid is belowa threshold value and wherein the fluid path between the bore and theoutlet channel is interrupted when the pressure of the fluid is abovethe threshold value.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a perspective view of an inflation device accordingto one embodiment. FIG. 1 illustrates a plunger assembly that is fullyinserted into the bore of a syringe body.

FIG. 2 is a plan view of the inflation device of FIG. 1. FIG. 2illustrates the plunger assembly partially retracted in the proximaldirection from the bore of the syringe body.

FIG. 3 is a cross-sectional view of the inflation device illustrated inFIG. 2. A shut-off valve is illustrated in the distal portion of thesyringe body.

FIG. 4 is an enlarged, cross-sectional view of the distal end of theinflation device illustrated in FIG. 3.

FIG. 5 is an enlarged, cross-sectional view of the distal end of theinflation device illustrated in FIG. 3 with the addition of a dashedline illustrating the flow path of a fluid used in conjunction with theballoon inflation device. In this configuration, the inflation fluidexits the valve body and passes through an outer channel that is influid communication with an outlet of the syringe body.

FIG. 6A is enlarged, cross-sectional view of the distal end of theinflation device illustrating an intermediate sealing member directlyblocking an outlet aperture in the valve body of the shut-off valve. Inthis position, fluid is prevented from exiting the valve body.

FIG. 6B is enlarged, cross-sectional view of the distal end of theinflation device illustrating the intermediate sealing member movingdistally with respect to the outlet aperture in the valve body of theshut-off valve. This state may reflect additional pressure being appliedto the plunger assembly as compared to the pressure applied in FIG. 6A.The outlet aperture is straddled by the intermediate sealing member andthe proximal sealing member. Even in this position, fluid is preventedfrom exiting the valve body because of the straddling sealing members.

FIG. 7 is a cross-sectional view of the inflation device illustratingthe plunger assembly being withdrawn proximally. Proximal retraction ofthe plunger assembly is employed to deflate the inflatable balloon.

FIG. 8 is an enlarged, cross-sectional view of the distal end of theinflation device. The moveable piston of the shut-off valve isillustrated abutting a proximal stop within the interior of the syringebody. The proximal stop prevents unwanted or excess movement of themoveable piston when the plunger assembly is withdrawn in the proximaldirection to deflate the inflation balloon.

FIG. 9 illustrates a cross-sectional view of a portion of the proximalend of the inflation device. The shaft of the plunger assembly isillustrated with a plurality of detents disposed longitudinally alongthe length of the shaft. A projection or flange on the syringe bodyinterfaces with the detents to provide tactile and/or audible feedbackregarding the position of the shaft within the bore of the syringe body.The interface between the detents and the projection or flange may alsoact as a temporary lock between the syringe body and the plungerassembly.

FIG. 10 is a perspective view of an inflation device coupled to aballoon catheter via a connector such as, for instance, a Luerconnector. The balloon is illustrated in an inflated state as theplunger assembly has been advanced distally within the syringe bore.

FIG. 11 illustrates an inflation device coupled to a balloon catheterthat is situated within a cannula. The cannula is a dual-lumen cannulathat includes a first port or opening for insertion of the ballooncatheter. A second port or opening in the cannula communicates with asecondary lumen that is sized to receive a visualization device such asan endoscope. The endoscope is illustrated as being disposed in thecannula.

FIG. 12 illustrates a system incorporating the inflation devicedescribed herein. The system is used to access and treat the naturalmaxillary sinus ostium.

FIG. 13 illustrates an access tool and access sheath used to access themaxillary sinus of a patient via the canine fossa.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

FIGS. 1 and 2 illustrate a inflation device 10 that is used to dilate orinflate an expandable member such as a dilation balloon 100 (illustratedin FIGS. 10-12) that is disposed on a distal end of an elongate member102 (also illustrated in FIGS. 10-12) such as a balloon catheter 104.The inflation device 10 is configured as an actuator that is used toselectively push or pull a substantially incompressible fluid into orout of the dilation balloon 100. The inflation device 10 may take theform of a syringe or the like. For example, in the embodimentillustrated in FIGS. 1 and 2, the inflation device 10 includes a syringebody 12 that includes a proximal end 14, a distal end 16, and a centralbore 18 (better seen in FIGS. 3-5, 6A, 6B, and 7-9). The syringe body 12is typically made from a polymer material such as polycarbonate or otherplastic-based materials although a variety of materials may be used. Theshape of the syringe body 12 is typically cylindrical although theinvention is not limited to any particular geometrical shape. Thecentral bore 18 defines an internal volume of the syringe body 12 thatis configured to hold a fluid such as saline. The total availableinternal volume of the syringe body 12 may vary but typically is withinthe range of 0 mL to about 2.2 mL. Not all of this total availablevolume may be used, however. For example, actual volume of fluidcontained in the syringe body 12 after priming may be in the range ofabout 1.5 mL to about 2.0 mL. The length of the syringe body 12 may alsovary but typically the central bore 18 portion is within the range ofabout 2.5 inches to about 3 inches.

The proximal end 14 of the syringe body 12 may include one or moreoptional flanges 20, 22 disposed about the periphery of the syringe body12. The flanges 20, 22 may be formed as circular or elliptical-shapedaprons that define a recess 24 that may be used to place one or morefingers during operation of the inflation device 10. For example, therecess 24 formed between the proximal flange 20 and the distal flange 22may be used by the physician or other user to place his or herforefinger (or other/additional finger(s)) during actuation of theinflation device 10. The exact shape and dimensions of the flanges 20,22 may be tailored to ensure a comfortable, ergonomic fit with theuser's hands.

Still referring to FIGS. 1 and 2, the distal end 16 of the syringe body12 includes a connector 26. The connector 26 may be affixed to thesyringe body 12 as a separate structure or, alternatively, the connector26 may be integrally formed with the syringe body 12 (e.g., molded aspart of syringe body 12). For example, the connector 26 may include ahousing 29 that extends proximally and is bonded to or otherwise securedto the syringe body 12. The connector 26 includes an aperture 28 (bestseen in FIG. 2 and later FIGS) that, except during actuation of ashut-off valve 50 described in more detail below, is in fluidiccommunication with the with the central bore 18 of the syringe body 12.In this regard, fluid is able to pass through the connector 26 as theinflation device 10 is actuated. The connector 26 may include any numberof connectors typically used to connect medical components to oneanother. One such connector 26 is a Luer connector which is illustratedin FIGS. 1-5, 6A, 6B, 7, 8, and 10-12. Luer connector 26 has a threadedportion 27 that is configured to engage with a mating interface orconnector. Other such connectors 26 are, however, contemplated to fallwithin the scope of the invention.

The inflation device 10 further includes a plunger assembly 30 that isdimensioned for insertion into the bore 18 of the syringe body 12. Theplunger assembly 30 includes an actuator 32 that is coupled to aproximal end 33 of shaft 34. The actuator 32 may be formed as a ring orthe like as illustrated in FIGS. 1 and 2. In this regard, the ring isdimensioned to that the physician's (or other user's) thumb may beinserted within the ring. Movement of the actuator 32 in the proximaldirection will remove the shaft 34 from the bore 18 of the syringe body12. Conversely, movement of the actuator 32 in the distal direction willadvance the shaft 34 into the bore 18 of the syringe body 12.

Turning now to FIG. 3, the shaft 34 is an elongate structure that isdimensioned to fit within the bore 18 of the syringe body 12. The distalend 36 of the shaft 34 includes a sealing member 38 that forms a fluidicseal between the shaft 34 and the internal surface of the syringe body12 defined by the bore 18. As seen in FIG. 3, the sealing member 38 maybe formed from an o-ring that is located in a recess 40 located at thedistal end 36 of the shaft 34. The shaft 34 may optionally incorporateone or more detents 42, 44, 46 located at different locations along theshaft 34. For example, there may be a distal detent 42, an intermediatedetent 44, and a proximal detent 46. As explained in more detail below,in certain embodiments, the detents 42, 44, 46 may provide tactileand/or audible feedback to the user to facilitate the prepping and useof the inflation device 10.

Referring now to FIGS. 3 and 4, a shut-off valve 50 is located at thedistal end 16 of the syringe body 12. The shut-off valve 50 is designedto permit passage of fluid (e.g., saline) from the bore 18 of thesyringe body 12 and out the aperture 28 of the connector 26 up to athreshold or pre-set pressure level. Once the threshold or pre-setpressure level has been exceeded, the design of the shut-off valvelimits additional fluid from exiting the inflation device 10.

The shut-off valve 50 is located within a valve body 52 or housingcontained at the distal end 16 of the syringe body 12. The valve body 52may be integrally formed with the syringe body 12 or, alternatively, thevalve body 52 may be a separate structure that is bonded, welded, ormolded together with the syringe body 12. For instance, the shut-offvalve 50 may be physically separate from the syringe body 12 andattached via a piece of tubing or similar conduit. The shut-off valve 50may be disposed outside or external to the syringe body 12. The valvebody 52 includes a proximal end 54 and a distal end 56. The proximal end54 of the valve body 52 includes an inlet aperture 58 that fluidicallycommunicates with the bore 18 of the syringe body 12 and enables fluidto enter the valve space 60. The distal end 56 of the valve body 52includes an end cap 62. The end cap 62 includes a mount 64 or the likefor receiving one end of a compression spring 66. The opposing end ofthe compression spring 66 is mounted on a moveable piston 68.

As explained in more detail below, the moveable piston 68 moves distallyand proximally within the valve space 60 as the plunger assembly 30 isadvanced or retracted within the bore 18 of the syringe body 12. Themoveable piston 68 includes a distal sealing member 70, an intermediatesealing member 72, and a proximal sealing member 74. In one aspect, thesealing members 70, 72, and 74 may include o-rings 70, 72, and 74 ascurrently illustrated in the drawings. The various o-rings 70, 72, 74are mounted about the moveable piston 68 in respective grooves 76, 78,and 80. The o-rings 70, 72, 74 create a fluidic seal between theexternal surface of the moveable piston 68 and the interior surface ofthe valve body 52. As best seen in FIG. 4, the moveable piston 68contains a bypass lumen 82 that communicates at one end with the valvespace 60 and terminates at an outlet 84 located on the side of themoveable piston 68.

As best seen in FIG. 4, an aperture 86 is located in the valve body 52and depending on the position of the moveable piston 68, is fluidicallyconnected to the fluid contained in the bypass lumen 82. The aperture 86located in the valve body 52 opens to an outlet channel 88 that isformed between the exterior surface of the valve body 52 and the housing29. The outlet channel 88 fluidically communicates with the aperture 28of the connector 26. In the orientation seen in FIG. 4, a fluid such assaline is able to enter the valve space 60 via the inlet aperture 58. Aspressure is applied to the fluid by the plunger assembly 30, the fluidpasses into the bypass lumen 82 and then through the aperture 86 intothe outlet channel 88. The fluid can then continue through the outletchannel 88 and out the aperture 28 of the connector 26. The fluid wouldcontinue along the elongate member 102 and into the dilation balloon 100(illustrated in FIGS. 10-12).

In the configuration of FIG. 4, the aperture 86 of the valve body 52 isillustrated as being straddled by the distal o-ring 70 and theintermediate o-ring 72. In this configuration, a flow path isestablished between the bore 18 and the aperture 28 of the connector 26.The flow path is illustrated in dashed line A in FIG. 5. The position ofthe shut-off valve 50 illustrated in FIGS. 4 and 5 reflects a “neutral”position, which is a condition wherein the fluid pressure within thebore 18 of the syringe body 12 is lower than the pressure required toactivate the shut-off valve 50. In this neutral position, fluid is ableto exit the inflation device 10 and enter the elongate member 102 anddilation balloon 100 (illustrated in FIGS. 10-12). It should also benoted that, in one alternative embodiment, the distal o-ring 70 may beoptional. Having a distal o-ring 70 does, however, prevent fluid fromentering the space within the shut-off valve 50 occupied by thecompression spring 66.

As described herein, the piston 68 is moveable within the valve space60. As the pressure of the fluid within the bore 18 is increased (byadvancing the actuator 32 and shaft 34 distally), additional fluid isforced into the valve space 60. This forces the moveable piston 68 toslide distally and results in compression of the compression spring 66.The compression spring 66 will absorb this motion by compressing acommensurate amount to the pressure that is applied to the piston 68. Asthe pressure is increased to higher and higher values, the piston 68 ismoved further distally until such point where the intermediate o-ring 72covers or blocks the aperture 86. This state is illustrated in FIG. 6A.Once the aperture 86 is covered or otherwise blocked by the intermediateo-ring 72, the fluid communication path A to the aperture 28 of theconnector 26 (and dilation balloon 100) is interrupted. Thisinterruption of the flow path A prevents higher pressures within thebore 18 from being transferred to the dilation balloon 100. If a userapplies additional pressure by depressing the plunger assembly 30further within the syringe body 12, the moveable piston 68 will continueto advance distally. This state is illustrated in FIG. 6B.

Even though the intermediate o-ring 72 has moved distally with respectto the aperture 86, fluid flow is prevented from reaching the aperture86 and outlet channel 88 because of the proximal o-ring 74. So long asthe intermediate o-ring 72 and the proximal o-ring 74 straddle theaperture 86, fluid communication between the bore 18 and the attachedelongate member 102 (e.g., balloon catheter 104) is interrupted.

FIG. 6B illustrates the configuration of the pressure shut-off valve 50at the condition where the pressure within the syringe body 12 (e.g.,bore 18) is above the pre-specified pressure threshold which activatesthe shut-off valve 50. The moveable piston 68 has been advanceddistally, until the piston 68 has fully compressed the spring 66.Alternatively (or additionally), the moveable piston 68 has advancedagainst the spring mount 64 of the end cap 62. The spring mount 64 thusacts as a stop for the piston 68. The compressed spring 66 and/or thespring mount 64 further limits distal advancement of the piston 68,regardless of how high the pressure in the bore 18 of the syringe body12. In the position illustrated in FIG. 6B, the intermediate o-ring 72and the proximal o-ring 74 interrupt the fluid path A to the ballooncatheter 104, thus maintaining the pressure delivered to the ballooncatheter 104 at the desired pre-set value. Therefore, the pressureapplied to the dilation balloon 100 is limited by whatever pressure isrequired to compress the compression spring 66 to the point at which thefluid flow path A is interrupted by the intermediate o-ring 72 locatedon the moveable piston 68.

When it is desired to deflate the balloon catheter 104, the plungerassembly 30 is withdrawn proximally, as shown in FIG. 7. As the actuator32 and shaft 34 are withdrawn proximally from the syringe body 12, themoveable piston 68 will also move in the proximal direction in responseto the resultant decrease in pressure. When the moveable piston 68achieves the “neutral” position, such as that illustrated in FIG. 4,fluid communication to the dilation balloon 100 is re-established,thereby allowing the fluid in the balloon catheter 104 to be withdrawnfrom the dilation balloon 100 into the bore 18 of the syringe body 12.Preferably a proximal stop 90 (illustrated in FIG. 8) prevents excessivemovement of the piston 68 proximally such that under any negativepressure, fluid communication to the balloon catheter 104 remains open.The proximal stop 90 is an abutment that contacts the proximal end 54 ofthe moveable piston 68.

The desired maximum pressure that the balloon is exposed to can be“designed” into the shut-off valve 50 by varying one or more variablesof components of the shut-off valve 50, as would be known to thoseskilled in the art. For example, a “stiffer” vs. “softer” compressionspring 66 will result in a higher pressure require to shut off thevalve. Alternatively, design variables associated with the amount oftravel of the piston (shut-off “activation”) can be considered. For agiven compression spring 66, a shorter vs. longer distance from the“neutral” position to a “stopped” position determined by the position ofthe distal stop 64 (and associated position of the outlet) will alterthe pressure required to activate the shut-off valve 50. For example, ifthe stop 64 is positioned (and associated variables such as position ofthe outlet aperture are positioned) to effectively shorten the amount ofcompression required to close the outlet, the resultant “activationpressure” pressure for shutting off the shut-off valve 50 will be lower.The diameter of the piston 68 (and associated components such as theo-ring seals and piston lumen) will also impact the pressure at whichthe shut-off valve 50 interrupts fluid communication. All other thingsbeing equal, a larger diameter piston 68 will result in a lower pressurerequired for shut-off.

Referring now to FIG. 9, in one embodiment, the shaft 34 of the plungerassembly 30 incorporates one or more detents 42, 44, 46 that operate incooperation with a projection 92 located at the proximal end 14 of thesyringe body 12. The projection 92 may include a ring, lip or bump thatcircumferentially or intermittently circumscribes the entrance to thebore 18 of the syringe body 12. As seen in FIG. 3, there are threecircumferential detents about the shaft 34 including a distal detent 42,an intermediate detent 44, and a distal detent 46. The size andflexibility of the projection 92 is dimensioned to nest within therespective detents 42, 44, 46 as the shaft is moved axially within thesyringe body 12. The detents 42, 44, 46 provide tactile and/or audiblefeedback to the user to facilitate prepping and use of the inflationapparatus during a dilation procedure. For example, the shaft 34 may“click” into place as the user advances or retracts the shaft 34 withinthe bore 18 of the syringe body 12. The “click” may be felt and/or heardby the user.

The proximal detent 46 is located adjacent to the actuator 32 andinterfaces with the projection 92 when the plunger assembly 30 iscompletely advanced in the distal direction (e.g., as seen in FIGS. 1and 12). This configuration is preferably how the inflation device 10 isstored prior to use. In this position, the projection 92 is maintainedin a relaxed or “unflexed” condition, free from potential creeping.

To prep the inflation device 10, the connector 26 (with no ballooncatheter 104 attached) is placed in saline or other inflation fluid. Theplunger assembly 30 is then fully withdrawn in the proximal direction byproximal movement of the actuator 32. The shaft 34 is withdrawnproximally such that the intermediate detent 44 passes the projectionand the distal detent 46 engages with the projection 92. Residual airmay be present in the bore 18 of the syringe body 12 together with thefluid. This air is preferably expunged by tilting the inflation device10 upwards so that the connector 26 is higher in elevation than theremainder of the inflation device 10. The air or any other trapped gaseswill naturally rise towards the distal end 16 of the inflation device10. The plunger assembly 30 is then advanced by distal advancement ofthe actuator 32 until the intermediate detent 44 is engaged. At thispoint, the inflation device is fully prepped with a desired volume offluid, and ready to be connected to the balloon catheter 104 via theconnector 26.

As described above, the dilation balloon 100 is inflated by advancingthe plunger assembly 30 distally into the bore 18 of the syringe body12. The pressure shut-off valve 50 responds to increasing pressurewithin the syringe body 12 by closing the fluid flow path A (illustratedin FIG. 5) to the balloon catheter 104 at a pre-prescribed or thresholdpressure. Once the shut-off valve 50 is closed, higher pressuresimparted to the fluid contained within the syringe body 12 are nottransferred to the balloon catheter 104. Therefore, the pressure in theballoon catheter 104 will remain at a relatively constant pre-prescribedpressure and no higher.

To deflate the dilation balloon 100, the plunger assembly 30 is fullywithdrawn proximally by proximal retraction of the actuator 32 until thedistal detent 46 is engaged with the projection 92. The distal detent 46serves to keep the plunger assembly 30 in this position and holds thepartial vacuum pressure that has been established within the bore 18.This condition is maintained even if the user removes his or her handsfrom the actuator 32 or even if the entire the inflation device 10 islet go. As pressure in the bore 18 of the syringe body 12 is reduced bywithdrawal of the plunger assembly 30, the pressure shut-off valve 50 isre-opened, allowing for deflation of the dilation balloon 100 as theplunger assembly 30 is further withdrawn. Upon fully withdrawing theplunger assembly 30, the balloon catheter 104 is exposed to partialvacuum pressure.

The desired maximum pressure that the dilation balloon 100 is exposed tocan be designed into the shut-off valve 50 by varying one or morevariables of the components making the shut-off valve 50. For example, a“stiffer” compression spring 66 (i.e., a higher spring constant) willresult in a higher pressure required to actuate the shut-off valve 50.Alternatively, design variables associated with the amount of travel ofthe moveable piston 68 (shut-off “activation”) can be considered. For agiven compression spring 66, a shorter vs. longer distance from the“neutral” position (e.g., FIG. 5) to a “stopped” position (FIG. 6B)determined by the position of the distal stop 64 will alter the pressurerequired to activate the shut-off valve 50. For example, if the stop 64is positioned (and associated variables such as position of the outlet84 of the bypass lumen 82 and the aperture 86 are positioned) toeffectively shorten the amount of compression required to close theshut-off valve 50, the resultant “activation pressure” required foractuating the shut-off valve 50 will be lower. The diameter of themoveable piston 68 (and associated components such as the o-rings 70,72, 74 and bypass lumen 82) will also impact the pressure at which theshut-off valve 50 interrupts fluid communication.

In one embodiment, the pressure shut-off valve 50 is configured to shutoff at 12 atmospheres of pressure. In this embodiment, the compressionspring 66 has an elastic constant of 10 lb/in, such that when it iscompressed to the point where the distal stop 64 is engaged 0.65 inches,a force of 7.3 lbs is required. The outer diameter of the moveablepiston 68 and o-rings 70, 72, 74 are 6.1 mm. The bore 18 is preferablyabout 6.35 mm in diameter and 6.35 cm in length when the plungerassembly 30 is fully withdrawn (at full vacuum), which results in arelatively small volume and overall size when compared to prior artinflation devices.

As best seen in FIG. 4, the connector 26 may be integrally formed with ahousing 29 that extends proximally and is mounted coaxially around theshut-off valve 50. This housing 29 is then secured to the syringe body12. While numerous suitable methods may be employed, such as adhesive orsolvent bonding, or ultrasonic welding, a preferred method is to “spinweld” the two components together. The housing 29 and the syringe body12 are dry fitted together and then spun relative to each other togenerate friction. This friction melts some of each material, forming astrong hermetic weld between the two components. In a likewise fashion,the projection 92 can be secured to the syringe body 12.

In one embodiment of the inflation device 10, there is no separatepressure gauge as is commonly found using prior art balloon catheterinflation devices. As a result, there is no “dead space” air volume. Theinflation device 10 can therefore be “primed” with fluid with neartotality. With little or no air in the inflation device 10, the volumeof the syringe body 12 and the priming volume can be relatively smalland still provide an adequate vacuum pressure to deflate the dilationballoon 100. In a preferred embodiment, the priming volume within thebore 18 of the syringe body 12 is 1.75 mL. In such an embodiment, one ormore small indicators 94 (best illustrated in FIGS. 1, 2, 4, 5, 6A, 6B,8 and 10-12) can be incorporated into the syringe body 12 to visiblyobserve the movement of the movable piston 68. Such indicators 94 can bepositioned to correspond to the position of a location on the movablepiston 68, e.g. the distal o-ring 70 at varying pressures to serve as asimple pressure gauge.

The relatively small size of the inflation device 10, coupled with theability to be operated with one hand provides for an inflation apparatusthat can be “directly connected” to the balloon catheter 104. Preferredballoon catheters 104 that may be used with the inflation device 10described herein are described in U.S. patent application Ser. Nos.11/379,691 and 11/623,740, which are incorporated by reference herein.As such, it is contemplated that a dilation system including the ballooncatheter 104 and the inflation device 10 can be used by a singleoperator or, alternately, can be used more traditionally with two ormore operators.

FIG. 10 illustrates the inflation device 10 coupled to a ballooncatheter 104. The balloon catheter 104 generally includes an elongatemember 102 that has a proximal end 106 and a distal end 108. A dilationballoon 100 is disposed on or near the distal end 108 of the elongatemember 102 and the interior portion of the dilation balloon 100 isfluidically coupled to a lumen (not shown) that extends the length ofthe elongate member 102. This lumen carries the fluid (e.g., saline)that is delivered via the inflation device 10 when the balloon catheter104 is connected. As seen in FIG. 10, the proximal end 106 of theelongate member 102 terminates in a connector 110 that is configured toconnect to the connector 26 disposed at the distal end 16 of theinflation device 10. The connector 100 may include a mating Luerconnector to connect with the one illustrated in FIG. 10.

FIG. 11 illustrates the inflation device 10 that is coupled to a ballooncatheter 104 that is disposed within a cannula 120. The cannula 120 mayinclude a handle portion 121 that is configured to be grabbed orotherwise manipulated by the user. The cannula 120 includes a firstinlet port 122 that is configured to receive a balloon catheter 104. Theinlet port 122 leads to a first lumen (not shown) that extends to anelongate portion 124 of the cannula 120 and terminates at a distal end126. The balloon catheter 104 can thus be introduced (in a deflatedstate) into the first inlet port 122 and advanced distally through thecannula 120 to place the dilation balloon 100 distally with respect tothe distal end 126 of the cannula 120. The cannula 120 also includes asecond inlet port 128 that is configured to receive a visualizationdevice 130. The visualization device 130 may include, for example, anendoscope. The second inlet port 128 leads to a second lumen (not shown)that also extends to the elongate portion 124 of the cannula 120. Thevisualization device 130 can be introduced into the second inlet port128 and advanced distally through the cannula 120 to place a distal endof the visualization device 130 in a position to ascertain aforward-looking field of view (e.g., looking toward the dilation balloon100). Alternatively, the visualization device 130 may already beincorporated into the cannula 120 such that distal advancement is notnecessary. As explained below, the visualization device 130 is typicallyinserted into the cannula 120 prior to the insertion of the ballooncatheter 104.

The elongate portion 124 of the cannula 120 may be dimensioned such thatit can pass through an artificial opening formed into a sinus passagewayof a patient. For example, an artificial opening may be formed in thecanine fossa region of a subject using a tool or other implement such asthose disclosed in U.S. patent application Ser. Nos. 11/379,691,11/623,740, and 12/038,719 which are incorporated by reference herein.The artificial passageway that is formed in the canine fossa region maybe cannulated with a sheath or separate cannula as explained herein. Thesheath or separate cannula may then serve to create a working openingthrough which the elongate portion 124 of the cannula 120 may beintroduced.

As one exemplary method of using the system, the balloon catheter 104may then be guided under visualization to place a deflated dilationballoon 100 across a natural ostium such as the maxillary sinus ostium.Other ostia beyond the maxillary sinus ostium may also be treated inthis same fashion. The inflation device 10 as described in detail hereinmay then be used to dilate the dilation balloon 100 which is positionedwith the natural ostium. This procedure opens or reduces the degree ofconstriction of the natural ostium and reduces patient symptomsassociated with sinusitis.

FIG. 12 illustrates a balloon dilation catheter 104 placed across thenatural ostium of the maxillary sinus 140. The dilation balloon 100 isillustrated in a dilated state, after the inflation device 10 has beenactuated by distal advancement of the plunger assembly 30 within thesyringe body 12. FIG. 12 further illustrates the visualization device130 in the form of an endoscope being located in the second inlet port128. A visualization field 142 extends from the distal end of theendoscope 130 and provides the user with a view of the operative workingarea using the eyepiece 144 and/or a camera 146 connected to theendoscope 130. The operative working area may, for example, be displayedon a monitor or similar device (not shown) for easy viewing during theprocedure.

FIG. 12 illustrates the cannula 120 being positioned in the maxillarysinus 140 via an artificial opening created in the canine fossa regionof the patient. Also, the elongate portion 124 of the cannula 120 isillustrated as being positioned within an access sheath 150 thatincludes optional cutting surfaces 152. As explained in U.S. patentapplication Ser. No. 12/038,719, the cutting surfaces 152 createlongitudinally-oriented cutting surfaces at the outer perimeter of thedistal tubular member and permit the user to ream or “side-cut” theartificial passageway to re-orient the system after initial access ismade to the sinus cavity.

FIG. 13 illustrates the access tool 160 along with the access sheath150. The access tool 160 (e.g., trocar) includes a cutting orpenetrating tip 162 that is used to form the artificial passageway inthe canine fossa. When forming the artificial passageway in the caninefossa, the access sheath 150 is loaded onto the shaft of the access tool160. After the tissue has been penetrated, the access tool 160 can beremoved proximally, leaving the access sheath 150 in place.

For a typical procedure, the various components of the system areprovided as part of a sterile kit. For example, the kit may be packagedor boxed and include inflation device 10, the balloon catheter 104, thecatheter 120, access tool 160, and access sheath 150. The visualizationdevice 130 is typically not part of the kit. The individual items fromthe kit may then be removed in advance of use. Some users may prefer towithdraw the balloon catheter 104 and prepare the balloon catheter 104using a separate syringe device.

Alternatively, the balloon catheter 104 is primed using the inflationdevice 10 described herein. In particular, the end of the distal end 16of the inflation device 10 is placed in saline or other inflation fluid.The plunger assembly 30 is then fully withdrawn in the proximaldirection by proximal movement of the actuator 32 until the distaldetent 46 engages with the projection 92. Any entrained air is expungedby elevating the distal end 16 of the inflation device 10 and thenadvancing the actuator 32 until the intermediate detent 44 is engagedwith the projection 92. The inflation device 10 may be connected to theballoon catheter 104 via the connector 26 and set aside until neededlater in the procedure.

Next, the physician will then form the artificial passageway in thecanine fossa of the patient using the access tool 160 and access sheath150. The access sheath 150 is placed on the access tool 160 and apuncture is formed in the canine fossa region. The access tool 160 isthen withdrawn proximally leaving in place the access sheath 150.Optionally, the cutting surfaces 152 of the access sheath 150 may beused to ream out the artificial opening and reposition to the accesssheath 150 to the desired orientation. The visualization device 130(e.g., endoscope) is advanced into the cannula 120 and locked intoplace. Alternatively, the visualization device 130 may have already beenadvanced or otherwise secured to the cannula 120. The cannula 120 andvisualization device 130 are then advanced through the access sheath 150into the maxillary sinus cavity 140 (or other sinus cavity). Thisadvancement is typically done under visualization using a camera 146 orthe like that outputs the image onto a display where the physician mayview the visual field 142 in real time.

In the case where the natural sinus ostium of the maxillary sinus 140 isto be treated, the physician will locate the ostium using thevisualization device 130. After the correct orientation is made of thecannula 120, the physician then advances the balloon catheter 104 (withthe dilation balloon 100 in the deflated state) through the inlet port122 of the cannula 120. The balloon catheter 104 is advanced to traversethe natural sinus ostium of the maxillary sinus 140 with the dilationballoon 100. Once into position, the operator can then depress theactuator 32 and advance the shaft 34 until the piston 68 moves distallyto engage the mount 64 and the proximal detent 46 engages with theprojection 92. Typically, the piston 68 reaches the shut-off positionprior to the proximal detent 46 reaching the projection 92. At thispoint, the dilation balloon 100 is inflated with the fluid and thusexpands within the natural ostium. This is illustrated in FIG. 12. Somephysicians may deflate the dilation balloon 100 and then re-inflate thedilation balloon 100 one or more times to ensure that proper dilationwas accomplished.

Once treatment is complete, the dilation balloon 100 is deflated and theballoon catheter 104 is withdrawn proximally from the cannula 120. Thecannula 120 and the visualization device 130 are then removed from theaccess sheath 150. Finally, the access sheath 150 is removed from theartificially created opening.

While an entire procedure is described above in connection withapproaching a natural sinus ostium via the canine fossa, the toolsdescribed above, particularly the balloon catheter 104 and inflationdevice 10 could also be used in other procedures, for example fordilating a natural sinus ostium such as the maxillary sinus ostium or afrontal sinus ostium or a sphenoid sinus ostium via a transnasalapproach through the nostril.

While embodiments of the present invention have been shown anddescribed, various modifications may be made without departing from thescope of the present invention. The invention, therefore, should not belimited, except to the following claims, and their equivalents.

1. (canceled)
 2. A method of using an inflation device, comprising:filling an inflation device with a fluid, wherein the inflation devicecomprises: a syringe body having a bore that extends between a proximalend and a distal end, wherein the bore holds the fluid responsive tofilling the inflation device with the fluid, a plunger assembly that isslidable in the bore of the syringe body, wherein the plunger assemblycomprises a shaft having a sealing member configured to form a fluidtight seal with the syringe body, a distal connector disposed at thedistal end of the inflation device, wherein the distal connectorcomprises an aperture that is configured for passage of the fluid, afluid bypass channel disposed in the distal end of the syringe body andfluidically coupled to the aperture of the distal connector; and ashut-off valve coaxially disposed in the bore of the syringe body,wherein the shut-off valve comprises a spring-biased moveable pistonhaving a bypass lumen; moving the plunger assembly relative to thesyringe body, wherein moving the plunger assembly relative to thesyringe body comprises: responsive to a pressure of the fluid being lessthan a threshold value, forming, by the bypass lumen, a fluid pathbetween the bore and the fluid bypass channel in the syringe body,wherein the fluid bypass channel is formed between an exterior surfaceof the shut-off valve and an interior surface of the bore of the syringebody, and responsive to the pressure of the fluid being greater than thethreshold value, interrupting the fluid path between the bore and thefluid bypass channel.
 3. The method of claim 2, further comprising,responsive to forming the fluid path, supplying the fluid along thefluid path to the aperture of the distal connector.
 4. The method ofclaim 3, wherein the pressure of the fluid becomes greater than thethreshold value while supplying the fluid along the fluid path, andwherein, responsive to the pressure of the fluid being greater thanthreshold value, ceasing supplying the fluid along the fluid path to theaperture of the distal connector.
 5. The method of claim 4, furthercomprising coupling the inflation device to a proximal connector of aballoon dilation catheter, wherein the balloon dilation cathetercomprises an elongate member, a dilation balloon at a distal end of theelongate member, and the proximal connector at a proximal end of theelongate member.
 6. The method of claim 5, wherein supplying the fluidalong the fluid path to the aperture of the distal connector comprisesinflating the dilation balloon.
 7. The method of claim 6, whereinceasing supplying the fluid along the fluid path to the aperture of thedistal connector comprises maintaining a pressure of the fluid deliveredto the dilation balloon at a pre-set value.
 8. The method of claim 2,further comprising stopping movement of the plunger assembly relative tothe syringe body when the sealing member reaches one or more indicatorson a surface of the syringe body.
 9. The method of claim 2, wherein thethreshold value is 12 atmospheres.
 10. The method of claim 2, thespring-biased moveable piston comprises a spring having an elasticconstant of 10 pounds per inch.
 11. The method of claim 2, furthercomprising priming the inflation device with a priming volume in thebore of the syringe body of 1.75 milliliters.
 12. A method of using aninflation device, comprising: filling an inflation device with a fluid,wherein the inflation device comprises: a syringe body having a borethat extends between a proximal end and a distal end, wherein the boreholds the fluid responsive to filling the inflation device with thefluid, a plunger assembly comprising a shaft having a proximal end and adistal end, the proximal end of the shaft operatively coupled to anactuator, the distal end of the plunger assembly comprising a sealingmember configured to form a fluid tight seal with the syringe body, adistal connector disposed at the distal end of the inflation device,wherein the distal connector comprises an aperture that is configuredfor passage of the fluid, a shut-off valve disposed in a valve body,wherein the valve body and shut-off valve are coaxially located withinthe bore of the syringe body, wherein the shut-off valve is in fluidcommunication with the bore of the syringe body, wherein the valve bodyincludes an aperture that communicates with an outlet channel formedbetween an external surface of the valve body and an inner surface ofthe syringe body, wherein the aperture of the valve body is fluidicallycoupled to the aperture of the distal connector, wherein the shut-offvalve comprises a spring-biased moveable piston having a bypass lumen;moving the plunger assembly relative to the syringe body, wherein movingthe plunger assembly relative to the syringe body comprises: responsiveto a pressure of the fluid being less than a threshold value, forming,by the bypass lumen, a fluid path between the bore and the outletchannel in the syringe body, and responsive to the pressure of the fluidbeing greater than the threshold value, interrupting the fluid pathbetween the bore and the outlet channel.
 13. The method of claim 12,further comprising, responsive to forming the fluid path, supplying thefluid along the fluid path to the aperture of the distal connector. 14.The method of claim 13, wherein the pressure of the fluid becomesgreater than the threshold value while supplying the fluid along thefluid path, and wherein, responsive to the pressure of the fluid beinggreater than threshold value, ceasing supplying the fluid along thefluid path to the aperture of the distal connector.
 15. The method ofclaim 14, further comprising coupling the inflation device to a proximalconnector of a balloon dilation catheter, wherein the balloon dilationcatheter comprises an elongate member, a dilation balloon at a distalend of the elongate member, and the proximal connector at a proximal endof the elongate member.
 16. The method of claim 15, wherein supplyingthe fluid along the fluid path to the aperture of the distal connectorcomprises inflating the dilation balloon.
 17. The method of claim 16,wherein ceasing supplying the fluid along the fluid path to the apertureof the distal connector comprises maintaining a pressure of the fluiddelivered to the dilation balloon at a pre-set value.
 18. The method ofclaim 12, further comprising stopping movement of the plunger assemblyrelative to the syringe body when the sealing member reaches one or moreindicators on a surface of the syringe body.
 19. The method of claim 12,wherein the threshold value is 12 atmospheres.
 20. The method of claim12, the spring-biased moveable piston comprises a spring having anelastic constant of 10 pounds per inch.
 21. The method of claim 12,further comprising priming the inflation device with a priming volume inthe bore of the syringe body of 1.75 milliliters.